1. Field
The present invention relates to a transmitting apparatus and a transmitting method in which cross-connect information is used to transmit and receive a signaling message of a GMPLS function among plurality of nodes.
2. Description of the Related Art
Conventionally, a network manager managing a network performs cross-connect settings on all apparatuses (nodes) for path settings, such as a connection or branching from one arbitrary transmission path to another arbitrary transmission path. With this, an End-to-End path is established among the apparatuses forming the network.
In recent years, Multi-Protocol Label Switching (MPLS) has been used that allows an operation of a network with paths by introducing the concept of label switching into an Internet Protocol (IP) network. Also, Generalized Multi-Protocol Label Switching (GMPLS) has emerged, which is a technology of performing, in an autonomous distributing manner, an operation of a path networks, such as not only an IP network but also a Time Division Multiplexing (TDM) network and a Wavelength Division Multiplexing (WDM) network in Synchronous Digital Hierarchy (SDH)/Synchronous Optical NETwork (SONET), which is an international standard of a high-speed digital communication technique using an optical fiber (refer to Japanese Patent Application Laid-open Nos. 2005-20572 and 2006-287403). This GMPLS technology has been discussed for standardization in, for example Common Control and Measurement Plane (CCAMP)-Working Group (WG) Optical Internetworking Forum (OIF) of Internet Engineering Task Force (IETF) and International Telecommunication Union (ITU), and part of this technology is being put into practical use (refer to Request For Comment (RFC) 3471 and Request For Comment (RFC) 3473).
With reference to FIG. 16, End-to-End path establishment with GMPLS is explained, where the operation of a path network, such as a TDM network and a WDM network in SDH/SONET, is performed in an autonomous distributing manner. FIG. 16 is a diagram of a sequence of generating an End-to-End bidirectional path among apparatuses with GMPLS. As depicted in FIG. 16, transmitting apparatuses A to D are those such as TDM apparatuses or WDM apparatuses. When an End-to-End path is newly set among such transmitting apparatuses A to D by using a GMPLS function, a network manager specifies a start-point node (transmitting apparatus A) and an endpoint node (transmitting apparatus D). Then, the transmitting apparatuses A to D automatically perform route calculation, cross-connect settings, and other processes based on information about the specified start-point and endpoint to establish a path.
Specifically, when a start-point node and an endpoint node are specified by the network manager or the like at the transmitting apparatus A, the transmitting apparatus A, which is a start-point node, transmits to the transmitting apparatus B a path message (PathMsg: refer to FIGS. 17A and 18A) that specifies information about a route from the transmitting apparatuses A to D (Explicit_Route Object (ERO)), information about a band to be requested, and others (refer to (1) in FIG. 16).
Then, as with the transmitting apparatus A, the transmitting apparatus B, which is an intermediate node that receives the path message from the transmitting apparatus A, transmits to the transmitting apparatus C a path message with the route information, the band information, and others as being in a reserved state. Subsequently, the transmitting apparatus C, which is an intermediate node that receives the path message from the transmitting apparatus B, performs a process similar to that of the transmitting apparatus B to transmit a path message to the transmitting apparatus D.
Thereafter, the transmitting apparatus D, which is an endpoint node that receives the path message from the transmitting apparatus C, transmits to the transmitting apparatus C a reserve message (ResvMsg: refer to FIGS. 17B and 18B), which is a response message to the path message, and also performs path settings (cross-connect settings) on its own node (refer to (2) in FIG. 16).
Then, as with the transmitting apparatus D, the transmitting apparatus C, which is the intermediate node that receives the reserve message from the transmitting apparatus D, transmits a reserve message to the transmitting apparatus B and also performs path settings on its own node. Subsequently, the transmitting apparatus B which is the intermediate node that receives the reserve message from the transmitting apparatus C, performs a process similar to that of the transmitting apparatus C to transmit a reserve message to the transmitting apparatus A, and also performs path settings on its own node. Thereafter, the transmitting apparatus A, which is the start-point node that receives the reserve message from the transmitting apparatus B, performs path settings on its own node. As a result, bidirectional path settings from the transmitting apparatuses A to D are completed. FIGS. 17A and 17B depict a general signaling message for use in GMPLS. FIGS. 18A and 18B depict details of a general signaling message for use in GMPLS.
However, in the conventional technologies above, while the path is shifted to be under GMPLS management, the network service has to be once cut off and, consequently, a time occurs during which the network service cannot be provided.
Specifically, an existing path that has been present since the time before the GMPLS function is implemented cannot be managed as a path to be established with the GMPLS function. For this reason, to implement the GMPLS function in a network where the existing path has been established, all cross-connect settings that form the existing path have to be deleted, and then a path corresponding to the existing path has to be registered and set with the GMPLS function. As a result, while the path is being shifted to be under GMPLS management, the network service has to be once cut off and, consequently, a time occurs during which the network service cannot be provided.